Goodwill and Other Intangibles - Summary of Company's Intangible Assets (Detail) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2022	Sep. 30, 2021
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, Trademarks, net	$ 571,610	$ 618,259
Net Book Value	491,553	502,078
Finite-Lived Intangible Assets, Net [Abstract]
Accumulated Amortization	$ (80,057)	(116,181)
Trademarks—Other
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Remaining Amortization Years	14 years 1 month 6 days
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	$ 55,900	55,900
Accumulated Amortization	(9,772)	(8,079)
Net Book Value	46,128	47,821
Trademarks, net
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, Trademarks, net	365,900	365,900
Net Book Value	356,128	357,821
Finite-Lived Intangible Assets, Net [Abstract]
Accumulated Amortization	$ (9,772)	(8,079)
Customer lists
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Remaining Amortization Years	8 years 9 months 18 days
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	$ 91,028	91,563
Accumulated Amortization	(52,881)	(50,483)
Net Book Value	$ 38,147	41,080
Patents
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Remaining Amortization Years	7 years
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	$ 3,428	49,428
Accumulated Amortization	(1,518)	(47,389)
Net Book Value	$ 1,910	2,039
In-process research and development
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Remaining Amortization Years	4 years 9 months 18 days
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	$ 4,500	4,500
Accumulated Amortization	(2,325)	(2,100)
Net Book Value	$ 2,175	2,400
Developed technology
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Remaining Amortization Years	13 years 9 months 18 days
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	$ 87,000	87,000
Accumulated Amortization	(7,039)	(4,139)
Net Book Value	$ 79,961	82,861
Reacquired rights
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Remaining Amortization Years	2 years 3 months 18 days
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	$ 14,054	13,568
Accumulated Amortization	(4,216)	(2,035)
Net Book Value	$ 9,838	11,533
Non-compete agreement
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Remaining Amortization Years	1 year 9 months 18 days
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	$ 5,700	6,300
Accumulated Amortization	(2,306)	(1,956)
Net Book Value	3,394	4,344
Other intangible assets, net
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	205,710	252,359
Accumulated Amortization	(70,285)	(108,102)
Net Book Value	135,425	144,257
Trademark—Weber
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, Trademarks - Weber	310,000	310,000
Net Book Value	$ 310,000	$ 310,000